This invention relates to a reproducing apparatus and process for forming multiple copies of a document. Document damage is substantially reduced by forming the first copy while the document is moving and additional copies while the document is held stationary.
There are presently available commercial reproducing machines such as the Xerox 3100 LDC copier which include means for making multiple copies of a document and further which can be operated in different modes of operation. In one mode of operation the aforenoted copier can make copies from a moving document whereas in another mode of operation the copier can make copies of documents held stationary.
In U.S. Pat. No. 3,844,653 to Kelly, yet another reproducing apparatus is shown. This apparatus is adapted to form duplex copies or copies which include images on both sides of the sheet. The first side of the document is viewed using a belt-type feeder the document past a fixed slit exposure system. The document is then fed back to the document tray or on to a rotating drum where the second side of the document can be viewed by a second fixed slit exposure system. A mirror is provided which pivots between the respective slit exposure systems to automatically switch from one to the other depending on which side of the document is being copied. In this system a copy of the first side of the document is formed as it is fed to the second exposure device for copying its second side.
In U.S. application Ser. No. 549,684 to Ari Bar-on, there is disclosed a dual purpose document handling system. This apparatus is adapted for use with a machine adapted to operate in moving and stationary document exposure modes such as the aforenoted 3100 LDC copier. In accordance with the invention disclosed in this application, a belt-type document feeder is utilized as a document handling system for placing documents on a platen to provide a scanning optical exposure or for advancing the documents over the platen in synchronism with a photosensitive surface to provide a moving original exposure.
There are other document handling systems described in the prior art for use with either moving or stationary original exposure systems. The use of a document handling system with a stationary original exposure device has found commercial applicability. In the commercial systems a document is rapidly advanced on to a platen for viewing by the optics of the reproducing machine, and then rapidly advanced off the platen while a new document is advanced on. In order to provide sufficient throughput for the producing machine, it is necessary to advance the documents on and off the platen in less than about 1/2 second. This requires relatively high speeds as compared to the processing speed of the apparatus. For example, speeds of 30 to 40 inches per second are often used as compared to process speeds which may vary from 3 to 20 inches per second.
One of the difficulties encountered with document handling systems is their propensity to damage documents during operation. Since the documents may be quite valuable and sometimes irreplaceable, it is, of course, desired to minimize or eliminate this propensity for document damage. The present invention is directed toward a process and apparatus which should enable such a reduction in document damage by substantially reducing the speed of the document as it is advanced over the platen.